Aspartate aminotransferase, glutathione reductase and thiamin transketolase activities will be studied in the endometrium of mature, normally cycling female baboons, as biochemical probes to determine if altered sex hormone environments can produce localized alterations in either availability, transport or binding of coenzymes in the endometrium. Using these three coenzyme-dependent enzymes, we will study the relationship of vitamin B6, riboflavin and thiamin to the stage of the menstrual cycle, to pharmacologic contraceptive agents and to vitamin supplementation. Blood levels of these three enzymes as well as complete vitamin screens, cholesterol and triglyceride levels will be followed for comparison with endometrial data and to determine systemic relationships between pharmacologic contraceptives and coenzymes and their potential interaction with uterine metabolism. We believe the endometrium is potentially susceptible to localized interaction between sex steroids, coenzymes and ultimately, endometrial function.